1. Field of the Invention
Embodiments of the present invention generally relate to methods of cleaning a deposition chamber using a remote plasma source.
2. Description of the Related Art
In the fabrication of integrated circuits and semiconductor devices, materials such as oxides are typically deposited on a substrate in a process chamber, such as a deposition chamber, such as a chemical vapor deposition (CVD) chamber. The deposition processes typically result in deposition of some of the material on the walls and components of the deposition chamber. The material deposited on the chamber walls and components can affect the deposition rate from substrate to substrate and the uniformity of the deposition on the substrate.
Several methods of cleaning a deposition chamber have been developed. For example, a remote plasma source can be used to provide a source of free radicals, such as fluorine radicals, that react with deposited material in the deposition chamber, forming volatile compounds that can be removed from the deposition chamber. However, cleaning a deposition chamber using known remote plasma sources is a time consuming process. Remote plasma sources typically provide free radicals at a flow rate and an intensity that do not result in a level of free radical or ion bombardment that can damage the deposition chamber. However, more time is required to clean a chamber when a low intensity cleaning process such as a remote plasma clean process is used. A lengthy chamber cleaning period decreases the number of substrates that can be processed in a given time, since the chamber cannot be used for deposition during the cleaning period.
Providing in situ radio frequency (RF) power in the deposition chamber to generate a plasma of cleaning gases is another method that can be used to clean a deposition chamber. Reactive species generated in the plasma bombard and react with deposited material in the deposition chamber, forming volatile compounds that can be removed from the deposition chamber. The reactive species can also bombard the chamber and remove deposited material from the chamber surfaces. However, the reactive species often damage the chamber due to the energy imparted to the species in the chamber. Furthermore, the reactive species can react with the material forming the chamber lining and create undesirable contaminants that may land on and harm a substrate undergoing processing in the chamber. For example, if NF3 is introduced into a chamber, the fluorine ions generated in the plasma can combine with aluminum used as a lining material in the deposition chamber and form particles of aluminum fluoride.
The removal of contaminating particles from a deposition chamber is becoming increasingly important because the device sizes are becoming smaller and aspect ratios are becoming more aggressive. With smaller feature sizes and more aggressive aspect ratios, the size and number of contaminating particles must be minimized in order to maintain the performance of the device.
Therefore, there remains a need for a method of cleaning deposition chambers efficiently, while minimizing contaminant generation. Additionally, the development of new materials, such as carbon-doped oxides having low dielectric constants, which can serve as components of integrated circuits, has created a need for a method of cleaning chambers that are used to deposit the new materials which can be more difficult to remove from chamber surfaces than other dielectric materials, such as oxides.